Severe Tropical Cyclone Gertie

17 - 22 December 1995

Summary

At 0700 UTC 17 December 1995 a low-level circulation, which had originated along an active monsoon trough near Darwin, was evident north of Troughton Island off the Kimberley Coast. The system was north of a strong middle-level ridge and was track- ing towards the southwest. Strong upper easterlies continued over Indonesia and on 18 December 1995 the low moved under a lighter upper wind zone and intensified into a tropical cyclone by 0400 UTC on that day. It continued to intensify while moving towards a region of strong upper northwesterly winds over southern Western Australia. These winds were developing ahead of an approaching trough system in the westerlies. At 2100 UTC 18 December 1995 an eye became evident on the Broome radar and by 0300 UTC 19 December 1995 it reached category three intensity. The trough weakened the middle-level ridge south of the cyclone and during 19 December 1995 Gertie slowed down and by 1200 UTC while near peak intensity it commenced a southwards and later a southeastward track towards the east Pilbara coast. The cyclone crossed the coast at Mandora Station around 2300 UTC 19 December 1995. The station reported a pressure minimum of 968.4 hPa and a maximum wind gust of 40 m/s and suffered extensive damage to buildings and equipment. Gertie continued to track southeast overland and around 1000 UTC 20 December 1995 passed close to Telfer; however, only marginal gale conditions were experienced there.

Although subsequently weakening below tropical cyclone strength Gertie remained well defined as it crossed the continent and at 2300 UTC 21 December 1995 could be analysed as a MSL 994 hPa low between Kulgera and Marla in Central Australia. It continued moving east and at 2300 UTC 22 December 1995 lay near the town of Roma in the southern interior of Queensland. At this time it linked up with a trough system which at MSL extended from the north- ern New South Wales coast into the Tasman Sea. Ex Gertie with the trough moved towards the coast bringing thunderstorms and heavy rain to the Southeast Coast and a tornado sighting from the Rockhampton Meteorological Office. The low moved into the Coral Sea near Maryborough shortly after 1100 UTC 23 December 1995 and rapidly intensified and by 2100 UTC gales were being experienced along the south coast of Queensland. These coastal gales were maintained until 0600 UTC 24 December 1995. The centre of the low by this time was about 900 km east-north-east of Brisbane and ships were reporting winds to storm force on its southern side. By 2300 UTC 24 December 1995 the low had passed to the south of Noumea and had weakened.

At 0530 UTC 19 December 1995 a line of severe thunderstorms, which had formed in the cloudband which extended from Gertie onto the Western Australian coast, caused damage on its passage through Marble Bar. Thus, along with the tornado sighting at Rockhampton, Gertie was associated with gales and severe thunderstorms on both sides of the continent.